The present invention disclosed the deposition source installed in a chamber, heated by applied electric power to transfer heat to a vapor deposition material received therein and applying a vaporized deposition material generated therein to a substrate to form deposition organic electroluminescent layers onto the substrate, and comprising a vessel consisted of a top plate on which a vapor efflux aperture is formed, a side wall, and a bottom wall; a heating means for supplying heat to the deposition material received in the vessel, the heating means being capable of moving vertically; and a means for moving the heating means (or the bottom wall), the moving means (or the bottom wall) being operated in response to the signal of a sensing means on varied distances between the heating means and the surface of said deposition material. Thus, the heating means is moved downward (or the bottom wall) is moved upward by the moving means to maintain the distance between the heating means (or the substrate to be coated) and the surface of the deposition material at an initially-set value when the thickness of the deposition material is decreased.